Apparatus for erasing typewriter tape

ABSTRACT

A tape having a smooth surface upon which a low melting point ink has been flowed, has ink reflowed over those portions which have been struck by typewriter keys. To effect a redistribution of the ink on the tape, heat is imparted locally thereto, such heat being applied to the typewriter tape either by conduction or radiation. Alternatively, the ink may be caused to flow freely at ambient temperatures and then be permitted to dry to a film thickness.

United States Patent [72] Inventor Kie Y. Ahn

Bedford, NY. [21] Appl. No. 791,256 [22] Filed Jan. 15, 1969 [45] Patented Dec. 7, 1971 [73] Assignee international Business Machines Corporation Armonk, N.Y.

[54] APPARATUS FOR ERASING TYPEWRITER TAPE 9 Claims, 8 Drawing Figs.

[52] U.S.Cl 197/171, 197/150, 197/181 [51] 1nt.Cl B4lj31/14, B41j 27/00, B41j 29/16 [50] Field of Search 197/151, 171,181,150,182,1;117/2;219/461;337/139; 118/641, 60; 101/401 56} References Cited UNITED STATES PATENTS 956,602 5/1910 Pulsifer 118/60 3,170,008 2/1965 Levine 101/40l.1 UX 3,377,598 4/1968 Borman 197/171 X 3,477,368 11/1969 Spavloing 197/1 X 2,030,820 2/1936 James 219/461 2,647,188 7/1953 Poitras 337/139 X 2,657,157 10/1953 Francis 197/172 UX 2,706,228 4/1955 Welsh 337/139 X 2,906,389 9/1959 Bishop.... 197/171 3,102,824 9/1963 Newman 197/172 X 3,237,748 3/1966 Rifkin 1. 197/181 3,464,534 9/1969 Muncheryan 197/181 Primary Examiner- Robert E. Pulfrey Assistant Examiner-Stephen C. Pellegrino Attorneys-Hanifin and .lancin and Isidore Match ABSTRACT: A tape having a smooth surface upon which a low melting point ink has been flowed, has ink reflowed over those portions which have been struck by typewriter keys. To effect a redistribution of the ink on the tape, heat is imparted locally thereto, such heat being applied to the typewriter tape either by conduction or radiation. Alternatively, the ink may be caused to flow freely at ambient temperatures and then be permitted to dry to a film thickness.

PATENTEDIJEB mu 3.625334 SHEET 1 OF 2 I ATTORNEY PATENTEUDEB 719R 3.625334 SHEET 2 OF 2 SWITCH 5 ASSEMBLY AC VOLTAGE VARIAC TRANSFORMER SOURCE W v 100 102 as v FIG. 10

BACKGROUND OF THE INVENTION This invention relates to an apparatus for erasing typewriter tape. More particularly, it relates to such apparatus whereby the tape is rendered reusable and any intelligible matter imprinted on the tape is destroyed.

In the normal typing practice, a used tape or ribbon is discarded in a receptacle provided therefor. Such discarded tape may contain all sorts of information, including confidential, personal and other additional material which it is desired not to disclose. I-leretofore, in order to remove any discernible subject matter imprinted on a typewriter tape, it has been necessary to entirely destroy the tape such as by physical destruction. Alternatively, it has been necessary to deposit the tape in a restricted location. It is readily appreciated that the need for the total destruction of a tape or its being placed in a classified area is a cumbersome procedure which consumes time, disrupts routine and is quite uneconomical. Clearly, it would be quite desirable to overcome the problems as set forth hereinabove.

Accordingly, it is an important object of this invention to provide an apparatus and method for selectively erasing a typewriter tape as it is being used.

It is another object of this invention to provide an apparatus and method in accordance with the preceding object for selectively erasing a typewriter tape whereby the tape is rendered reusable.

It is a further object of this invention to provide an apparatus in accordance with the preceding objects for re-inking the areas on the tape which have been erased.

SUMMARY OF THE INVENTION Generally speaking and in accordance with the invention, there is provided in a typewriter which includes a pair of spools which function respectively as supply and takeup reels for typewriter tape depending upon which direction the tape is being moved in a path between the spools, means for selectively erasing portions of the tape. The latter means comprises a pair of erasing means disposed in said path and respectively adjacent to the spools, each of the erasing means being adapted to be placed into contact with the tape as the tape is moved between the reels. Also included in the invention are means for energizing the erasing means.

To enable re-inking of used portions of the tape which have been erased, there is provided a re-inking means which comprises an ink receptacle which is adapted to be placed into contact with the tape and means associated with the receptacle and adapted to be heated to thereby heat the ink.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing,

FIG. IA is a perspective view of a conventional typewriter;

FIG. 1B is a schematic depiction of a portion of the typewriter shown in FIG. IA which illustrates an arrangement in accordance with the principles of the invention;

FIG. 1C is a perspective diagram showing an illustrative embodiment of the heater and eraser assembly;

FIG. 1D is a schematic depiction of the electrical system in accordance with the principles of the invention;

FIG. 2 is a perspective depiction of one illustrative embodiment of a device suitable for use as a heater assembly in accordance with the invention;

FIG. 3 is a schematic diagram, partly in section, of another illustrative embodiment of a device suitable for use as a heater assembly according to the invention;

FIG. 4 is a perspective diagram of a device suitable for use as a re-inter according to the invention; and

FIG. 5 is a diagram which illustrates a circuit suitable for testing the efficacy of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Referring now to FIGS. lA-ID, there is shown therein a typewriter 10 having a housing 12, a keyboard 14, and a platen l6. Typewriter 10 is suitably of the conventional electric type. In FIG. 1B, the tape 8 is shown as being moved from right to left from a supply spool 20 to a takeup spool 26. Tape 8 is moved from the supply spool 20 and passes through a right-hand eraser assembly 22, a center guide 18 and a lefthand eraser assembly 24 to takeup spool 26.

As shown in FIG. 1C which is a depiction of an eraser assembly, a pair of idler rollers 32 and 34, respectively, maintain the directionality and tension of tape 8 as it moves past heater 36. The left-hand and right-hand eraser assemblies 24 and 22, not shown, such guides being obviously well-known in the art are suitably mounted in left corner and right corner guides, respectively. As shown in FIG. 1C which is a diagram for eraser assembly 22, assembly 24 being of the same structure as assembly 22, i.e., comprising a heater 36' which includes nichrome wire heater 40', such assembly consists of a heater 36 and idler rollers 32 and 34. A nichrome wire heater 40 is embedded in heater 36. The two wires of nichrome wire heater 40 of heater 36 are connected to switch assembly 38 as shown in FIGS. 13 and 1D. A pair of springs 44 and 46 impart appropriate tension to idler rollers 32 and 34. Takeup spool 26 is operative to cause typewriter tape 8 to traverse heater assemblies 22 and 24 and pressure rollers 19 as shown in FIG. 1A, to cause tape 8 to be steadily taken up by takeup spool 26.

A transformer 35, in association with a potential source 100 which may suitably be an alternating current voltage source, functions to provide electrical energy to electrical heaters 36 and 36', the output of transformer 35 being connected to either of eraser assemblies 22 and 24 through switch assembly 38 as shown in FIG. 1D. A pair oflights 50 and 52 (FIG. 1D,) may suitably be provided on typewriter 10 to provide respective indications of the operational conditions of leftand righthand eraser assemblies 22 and 24.

An illustrative embodiment of a device suitable for user as heater 36 is shown in FIGS. 2 and 3. As seen in FIG. 2, heater 36 may comprise a metal strip 60 which may suitably be of nichrome and of a bimetallic element 62 which is mounted on an insulating element 66. In its passage, tape 8 makes contact with strip 60. The output from transformer 35 is connected to strip 60 and bimetallic element 62. Strip 60 constitutes a rigid base portion of heater 36 and bimetallic element 62 constitutes a flexible member thereon, strip 60 and element 62 being separated by the insulating portion 66.

In the operation of a heater such as heater 36 or heater 36', when the temperature of strip 60 is below the temperature necessary for erasing material from tape 8, strip 60 and member 62 normally make contact to permit a flow of current through both strip 60 and bimetallic element 62. Flowing current heats metallic strip 60 whereby erasing can be effected. When the temperature of strip 60 reaches a chosen level which may suitably be preset, bimetallic member 62 bends outwardly to cause the circuit including transformer 35 to open. With such arrangement, the temperature of metallic strip 60, i.e. the erasing strip, is maintained at a relatively constant level.

In FIG. 3, there is shown another illustrative embodiment of a device suitable for use as heater 36. The device shown therein is a radiant lamp 71 having terminals 76 which is provided with a curved mirror surface 72, surface 72 being configured such that the radiant energy from the lamp filament 74 is effectively focused onto an erasing surface 70, erasing surface 70 suitably being provided with a heat absorbing coating. The terminals of lamp 71 are adapted to be connected to the output of transformer 35.

In FIG. 4 there is shown an illustrative embodiment of a cartridge in the event that it is desired to effect erasing of tape 8 by alternative means. In the operation of cartridge 80, tape 8 is fed from supply spool 20 through center guide 18 and the cartridge 80 to takeup spool 26. As used typewriter tape 8 traverses cartridge 80, in contact with a felt pad 82, ink is transferred to the tape surface. The viscosity of the ink is controlled by a heater wire 84 wound around cartridge 80 and which suitably can be connected to the output of transformer 35.

In further consideration of the operation of the invention, reference is again made to FIG. 18. It is again mentioned that FIG. 1B is a view of a portion of the typewriter shown in FIG. IA and schematically depicts several aspects relevant to the operation of the invention. In this connection, takeup spool 26 and supply spool 20 are capable of performing reciprocal functions i.c. spool 20 may become the takeup spool and spool 26 may become the supply spool. As shown in FIG. 1D, the left heater 36' is connected to transformer 35 and switch assembly 38. At the right, a similar heater 36 is connected to transformer 35 and operated by the same switch 38. The interlocks which drive the mechanisms of the typewriter determine which heater 36 or 36 is operable with the passage of tape 8. As tape 8 moves to the left, heater 36 on the left is energized and lamp 50 is illuminated. As tape 8 moves to the right, the heater 36 on the right is energized and indicator lamp 52 is illuminated.

In a particular design involving an embodiment of the invention, the heater eraser can suitably be made of a high-temperature plastic which has a nonsticking surface, Teflon being useful for this purpose. A heater having a diameter of 0.75 inches and an overall length of l inch has proven to be of a size which has effectively removed the impressions of a striking typewriter key. A heater wire such as those constituting nichrome wire heaters 40 and 40' having a diameter of 0.039 inches and consisting of insulated nichrome wire is threaded through four equally spaced holes, not shown in the body of heaters 36 and 36' respectively, the ends of this wire being connected as shown in FIGS. 18 and 1D.

For an illustrative operation of the heater 36 or 36 shown in FIGS. 1A, 1B and 1C, a suitable operational condition is one wherein an input power of 1.8 watts l.5 volts and 1.2 amperes) is supplied by a 1 17/25 volts stepdown transformer 35 which functions to maintain the circuit temperature of the high temperature plastic erasing material at approximately 100 C. during operation. At the foregoing power level, it was observed that the ink flowed smoothly on the typewriter tape 8 and that the typewriter tape 8 was not damaged or otherwise impaired.

It was also observed that the erasing operation of a heater 36 or 36' was substantially independent of typing speed. For a particular operational condition and a specific typewriter tape 8, the power level supplied to a heater 36 or 36' should appropriately be adjusted in accordance with the melting temperature of the ink on the tape 8 and the softening temperature of the supporting base material for the tape 8.

Relative to the operation of the invention by alternative means, the function of ink source 80 as shown in FIG. 4 is to replenish the ink which has been used up in the operation of tape 8 during typing operation. If tape 8 is reused without erasure followed by re-inking, the typing capability thereof for clean copies is reduced because ink on the surface of the tape 8 adjacent the paper or other material upon which writing is effected, has been measurably effectively reduced. In order to maintain a constant viscosity of ink during operation, ink source 80 has a heating wire 84 wound therearound which is conveniently powered by the same transformer, i.e. transformer 35 as the one which provides power for the erasing assemblies.

It is to be realized that within the scope and spirit of the invention modifications may be made. Thus, a typewriter tape 8 may be selected which has a significantly high softening temperature. Such temperature permits considerable flexibility in the nature and operation of the heater 36 or 36'. Whenever a thicker coating of ink during the re-inking is desired, the temperature of the heater 36 or 36' can be reduced and the viscosity of the ink can be decreased thereby and the ink itself may be made to have a higher viscosity. Conventional control circuits can be employed with the heater 36 or 36' and reinker of this invention to particularly accommodate to the typewriter controls effected by the keys of the typewriter. In this connection, there could readily be provided a pulsed heating and therefore erasure during a heating and typing cycle.

The arrangement shown in FIG. 5 constitutes an experimental apparatus which is suitable for testing the operation of the erasing assembly in accordance with the principles of the invention and is convenient in testing the heater 36 or 36' shown in FIGS. IA, 1B and 1C. In this connection, AC voltage source is connected to a variable transformer 102 which is turn connected to transformer 35 to establish a variable power source therefor. The output of transformer 35 is connected to heater wire terminals 40 which are threaded into heater 36. The input power to the heater 36 is suitably monitored by an ammeter I04 and a voltmeter 106.

While the invention has been particularly shown with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In a typewriter having a tape with a smooth surface upon which a low melting point ink has been flowed and a pair of spools which function respectively as supply and takeup reels for said typewriter tape depending upon which direction the tape is being moved, the improvement which comprises:

electrical circuit-actuable heating means disposed intermediate said spools and positioned to make contact with said tape to selectively heat portions of said tape to cause the ink to reflow from portions of said tape unstruck by type keys to portions of said tape struck by said type keys thereby erasing portions of said tape as said tape is moved between said spools; and

means in circuit with said heating means for energizing said heating means.

2. In a typewriter which includes a pair of spools which function respectively as supply and takeup reels for said typewriter tape depending upon which direction the tape is being moved in a path between said spools, the improvement which comprises:

a pair of electrical circuit-actuable heating means respectively disposed in said path adjacent said spools, each of said heating means being positioned to make contact with said tape to selectively heat portions of said tape to cause the ink to reflow from portions of said tape unstruck by type keys to portions of said tape struck by said type keys thereby erasing portions of said tape when said tape is moved between said spools; and

means in circuit with each of said heating means for energizing said heating means.

3. In the typewriter as defined in claim 2 wherein said heating means comprises a structure comprising a metallic element and a bimetallic element mounted on said metallic element, said bimetallic element being so chosen whereby, below a given temperature it is in contact with said metallic element and at said given temperature it breaks contact with said metallic element; and

wherein said energizing means is in circuit with said metallic element and said bimetallic element.

4. In a typewriter as defined in claim 3 wherein said metallic element comprises nichrome.

5. In a typewriter as defined in claim 2 wherein said heating means comprises a radiant lamp having an inner surface which is curved and mirrored in part, and planar in part said curved part being so chosen as to effectively reflect radiant energy onto said planar part, said planar part including a heat-absorbing material, the outer portion of said lamp opposite said planar part being positioned to make contact with said tape.

6. In a typewriter as defined in claim 2 wherein said energizing means comprises a potential source and means for connecting said source to said heating means.

7. In a typewriter as defined in claim 2 wherein said energizing means comprises an alternating current potential source whose output is applied to a transformer, the output of said transformer being applied to said heating means to energize said heating means.

8. In a typewriter which includes a pair of spools which function respectively as supply and takeup spools for said typewriter tape depending upon which direction the tape is being moved in a path between said spools, the improvement which comprises:

a pair of electrical circuit-actuable heating means respectively disposed intermediate said spools in a path adjacent said spools, each of said heating means being positioned to make contact with said tape to selectively heat portions of said tape to cause the ink to reflow from portions of said tape unstruck by type keys to portions of said tape struck by said type keys thereby erasing portions of said tape when said tape is moved between said spools an ink reservoir adjacent one of said spools in said path, said ink reservoir being operative to be heated and to make contact with said tape to re-ink said tape; and

means in circuit with said heating means and said ink reservoir for energizing said heating means and for heating said ink reservoir.

9. A typewriter as defined in claim 8 wherein said heating means comprises a metallic element and a bimetallic element mounted on said metallic element said metallic element being adapted to be placed in contact with said tape and wherein said ink reservoir comprises a receptacle containing ink, a wire wound around said receptacle for receiving energy for heating said ink in said receptacle, and a felt pad for absorbing ink from said receptacle and adapted to be placed in contact with said tape. 

1. In a typewriter having a tape with a smooth surface upon which a low melting point ink has been flowed and a pair of spools which function respectively as supply and takeup reels for said typewriter tape depending upon which direction the tape is being moved, the improvement which comprises: electrical circuit-actuable heating means disposed intermediate said spools and positioned to make contact with said tape to selectively heat portions of said tape to cause the ink to reflow from portions of said tape unstruck by type keys to portions of said tape struck by said type keys thereby erasing portions of said tape as said tape is moved between said spools; and means in circuit with said heating means for energizing said heating means.
 2. In a typewriter which includes a pair of spools which function respectively as supply and takeup reEls for said typewriter tape depending upon which direction the tape is being moved in a path between said spools, the improvement which comprises: a pair of electrical circuit-actuable heating means respectively disposed in said path adjacent said spools, each of said heating means being positioned to make contact with said tape to selectively heat portions of said tape to cause the ink to reflow from portions of said tape unstruck by type keys to portions of said tape struck by said type keys thereby erasing portions of said tape when said tape is moved between said spools; and means in circuit with each of said heating means for energizing said heating means.
 3. In the typewriter as defined in claim 2 wherein said heating means comprises a structure comprising a metallic element and a bimetallic element mounted on said metallic element, said bimetallic element being so chosen whereby, below a given temperature it is in contact with said metallic element and at said given temperature it breaks contact with said metallic element; and wherein said energizing means is in circuit with said metallic element and said bimetallic element.
 4. In a typewriter as defined in claim 3 wherein said metallic element comprises nichrome.
 5. In a typewriter as defined in claim 2 wherein said heating means comprises a radiant lamp having an inner surface which is curved and mirrored in part, and planar in part said curved part being so chosen as to effectively reflect radiant energy onto said planar part, said planar part including a heat-absorbing material, the outer portion of said lamp opposite said planar part being positioned to make contact with said tape.
 6. In a typewriter as defined in claim 2 wherein said energizing means comprises a potential source and means for connecting said source to said heating means.
 7. In a typewriter as defined in claim 2 wherein said energizing means comprises an alternating current potential source whose output is applied to a transformer, the output of said transformer being applied to said heating means to energize said heating means.
 8. In a typewriter which includes a pair of spools which function respectively as supply and takeup spools for said typewriter tape depending upon which direction the tape is being moved in a path between said spools, the improvement which comprises: a pair of electrical circuit-actuable heating means respectively disposed intermediate said spools in a path adjacent said spools, each of said heating means being positioned to make contact with said tape to selectively heat portions of said tape to cause the ink to reflow from portions of said tape unstruck by type keys to portions of said tape struck by said type keys thereby erasing portions of said tape when said tape is moved between said spools an ink reservoir adjacent one of said spools in said path, said ink reservoir being operative to be heated and to make contact with said tape to re-ink said tape; and means in circuit with said heating means and said ink reservoir for energizing said heating means and for heating said ink reservoir.
 9. A typewriter as defined in claim 8 wherein said heating means comprises a metallic element and a bimetallic element mounted on said metallic element said metallic element being adapted to be placed in contact with said tape and wherein said ink reservoir comprises a receptacle containing ink, a wire wound around said receptacle for receiving energy for heating said ink in said receptacle, and a felt pad for absorbing ink from said receptacle and adapted to be placed in contact with said tape. 